Production of diolefines



Patented Mar. 10, 1931 UNITED STATES PATENT -orlucr.

PAUL I'EILER, OI LUDWIGSHAI'EH-ON-TBE-BHDTE, 63m, ASSIGNOB T01. G. I'll- IBEN'INDUSTBII AITIENGESELLSCHAII'T, OBT-OH-THE-IAIN, GEBHANY,

A. CORPORATION OI GERMANY rnonuo'non or momrmns m nmwm Application ma December 12, 1928, Serial no. 325,057, and m cemm rebmar 11, ma.

This invention relates to improvements in the manufacture and production of diolefines having conjugated double carbon bonds.

It is known that by the treatment of hydrocarbons of the ethylene series with solutions of certain metal salts such as silver salts, mercu salts or cuprous chloride, solutions of ad itive compounds of the metal salts with the olefines in question are ob- 1 tained, from which the combined olefines can be readily split oflz by warming, evacuation and the hke.

I have now found that also the diolefines having conjugated double carbon bonds, such as butadiene and its homologues, enter into combination with metal salts, and that the compounds can likewise be split up again in a simple manner and practically without loss, into metal salts and diolefines. and that in this 2 way 'butadiene hydrocarbons can be recovcipitates of solid additive products can be obtained from butadiene or gases containing the same. Thus, for example, on agitatin a hydrochloric acid solution of cuprous ch oride with butadiene or gases contamin the same, a. yellowish precipitate is obtain of the solid additive compound of butadiene with cuprous chloride.

The resulting additive compounds can be decomposed, in 'a simple manner, into the corresponding metal salt and the butadienehydrocarbon. Thus, for example, on heating the additive compound of butadiene and cuprous chloride, or on warming it with hydrochloric acid, if desired in vacuo the butadiene is expelled, and the metal salt is recovered as such, or in solution. The resultin hydrochloric acid solution of cu rous chlori e may be used for the recovery 0? further amounts of butadiene. The temperature at which the said resulting additive compounds are decomposed de ends on the kind of the heavy metal salt an also on the pressure employed. jAccording to the present invention the additive compounds are graduallyheated until the temperature of decomposition is reached. This ma easily be seen by the evolution of the dio efines from the said compounds. Temperatures of decompositim usually range from about 30 to If it be desired to isolate butadiene from mixtures with gases which are only sparingly soluble. in solutions of metal salts, for example, hydrogen, nitrogen, oxygen, methane and the like, the gaseous mixture may simply be. washed with solutions of silver salts or mercury salts, and the resulting absorbed butadiene hydrocarbons can be expelled from the solution by warming, in vacuo if desired.

In the case, however, of gaseous mixtures which contain simple olefines in addition to butodiene,'it is preferable to employ solutions of such metal salts as will furnish precipitates of solid additive products with hydrocarbons of the butadiene series alone. Thus, for example, when a hydrochloric acid solution of cuprous chloride 1s employed, the additive compounds of ethylene, propylene and butylene remain in solution, whereas the additive compound of vbutadiene separates out in solid form and can be filtered oil? and treated for the production of pure butadiene, as already described. The olefines can be recovered from the filtrate by warming, in vacuo if necessary, or by decomposition with an acid.

The following examples will further illustrate the nature of the invention, which however is not restricted thereto.

a Emample 1 butadiene and 50 per cent of nitrogen,

are shaken up with 15 parts by volumeof a hydrochloric acid solution of cuprous chlor de, prepared from 300 grams of cuprous chloride, 1700 cc. of conmntrated hydrochloric acid (s gr. 1.185) and 200 cc. of water. A yellow eposit is formed, in which practically the whole of the butadiene is contained in combination with cuprous chloride. From this additive compound, the butadiene can be easily recovered by heating.

Eatample? 110 parts by volume of a mixture of 50 per cent 0 butadiene and 50 per cent of butylene, are shaken upwith 15 parts by volume of the hydrochloric acid solution of cuprous chloride described in Example 1. A yellow deposit is formed. The residual butylene contains only small quantities of 'butadiene. The yellow precipitate is filtered ofi and decomposed by means of hydrochloric acid, pure butadiene being thus obtained.

Ewample 3 A gas mixture which has the composition 38 per cent of butadiene, 43.6 per cent of hydro en, 15 per cent of methane and 3.4 per cent 0 nitrogen is treated at room-temperature in a scru bing tower with a 10-N silver nitrate-solution in which treatment the butadiene is absorbed by the silver nitrate. If 200 parts by volume of gas be passed through per hour and 4: parts by volume of silver nitrate be employed, the gas issuin from the solution is entirely free from buta iene. By heating the silver nitrate solution thus obtained. or evacuating it, the absorbed butadiene may be recovered in a substantially pure formr If the operation is carried out at lower temperatures, for example at about 0 (3., a much igher output of gases ma be attained. The

Example 4 A gas mixture having the composition 46.4 per cent of butadiene and 53.6 per cent of nitrogen is shaken up at room-temperature with a solution of mercurous nitrate obtained by dissolving 90 parts by weight of the said salt in 1000 parts of water. The whole of the butadiene is absorbed. If the solution thus obtained be heated or treated in vacuo, the absorbed butadiene is recovered in a practically pure form. Also in this case it is advantageous to carry out the absorption at low temperatures.

What I claim is 1. A process for the recovery of diolefines having conjugated double carbon bonds from gaseous mixtures containing the same, which comprises treating the said gaseous mixtures with a salt of a heavy metal from groups 1 and 2 of the periodic system, and liberating the said diolefines from the resulting additive compounds.

2. A process for the recovery of diolefines having conjugated double carbon bonds from gaseous mixtures containing the same, which comprises treating the said aseous mixtures with a solution of a salt 0 a heavy metal from ups 1 and 2 of the periodic system, and li crating the said diolefines from the resulting additive compounds.

3. A process for the recovery of diolefines having conjugated double carbon bonds from gaseous mixtures containing the same, which comprises treating the said gaseous mixtures with a salt of a heavy metal from groups 1 and 2 of the periodic system in the univalent form, and liberating the said diolefines from the resulting additive compounds.

4. A process for the recovery of diolefines having conjugated double carbon bonds from gaseous mixtures containing the same, which comprises treating the said gaseous mixtures with a solution of a salt of a heavy metal from groups 1 and 2 of the periodic system in the univalent form, and liberating the said diolefines from the resulting additive com- 1 pounds.

5. A process for the recovery of diolefines having conjugated double carbon bonds from gaseous mixtures containing the same, which comprises treating the said gaseous mixtures with a salt of copper in the univalent form and liberating the said diolefines from the resulting additive compounds.

6. A process for the recovery of diolefines having conjugated double carbon bonds from gaseous mixtures containing the same, which comprises treating the said gaseous mixtures with a solution of a salt of copper in the univalent form, and liberating the said diolefines'from the resulting additive compounds.

7. A process for the recovery of diolefines having conjugated double carbon bonds from gaseous mixtures containing the same, which comprises treating the said gaseous mixtures with a solution of cu rous chloride, and liberating the said diole nes from the resultingbadditive compounds.

testimony whereof I have hereunto set my hand.

PAUL FEILER. 

